[DIRMINA-1095] Seems like the management f UDP sessions is really unneficient

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.19
• Fix Version/s: 2.1.3, 2.0.23
• Assignee: Jonathan Valliere
• Reporter: Emmanuel Lécharny
• Created: 29/Sep/18 03:32
• Updated: 04/May/19 17:19
• Resolved: 04/May/19 17:11

Description

When we process incoming UDP messages, we iterate over the activated {{SelectionKey}}s. That's ok, but for each one of them, we read the data and try to flush the scheduled messages. The loop where it's done seems to iterate on all the managed sessions, for each keys we are processing :

   private void processReadySessions(Set<SelectionKey> handles) {
        Iterator<SelectionKey> iterator = handles.iterator();

        while (iterator.hasNext()) {
            SelectionKey key = iterator.next();
            DatagramChannel handle = (DatagramChannel) key.channel();
            iterator.remove();

            try {
                if (key.isValid() && key.isReadable()) {
                    readHandle(handle);
                }

                if (key.isValid() && key.isWritable()) {
                    for (IoSession session : getManagedSessions().values()) {
                        scheduleFlush((NioSession) session);
...

There is no reason to do so. First, we should not iterate on all the managed sessions (we may have thousands), but only the sessions which have something to write, and we certainly should not do that for every active key...